Expanding their range

A story of survival of the desert bighorn sheep in the county’s Sespe Wilderness

The cliff face rose just a bit more than 1,000 feet from the canyon floor to a distinct V-notch right below the rolling ridgeline. Scrambling up an alluvial fan of crumbly, loose shale I made my ascent toward the notch into the heart of desert bighorn sheep (Ovis canadensis nelsoni) habitat deep in the Sespe Wilderness.

The night before, friend Danny Trudeau and I were searching for a reliable water source after 15 dusty miles on the trail, when the last of a winter sun dipped beyond the daunting Topa Topa Mountains to the west. After finding a spring in a narrow canyon beneath a cottonwood tree, we hiked back to our tents. Two canyons west of us, there they were.

“There’s some bighorn up on the ridge above us,” said Trudeau, pointing southward. At dusk, 2,000 feet above us we caught our first glimpse of 13 nimble-footed desert bighorn sheep traversing eastward toward a craggy ridgeline ensconced in mazanita and sage.

A group of younger desert bighorn huddle together last December during a freeze.

Bighorn scrambleDesert bighorn sheep are found in seven western states, including Texas, New Mexico, Arizona, Nevada, Colorado, Utah and California. Over the past century, desert bighorn sheep populations have declined by as much as 90 percent. Disease from domestic livestock has historically been a prime culprit. Current threats to their existence have been free-roaming grazing livestock that reduces reliable food sources and habitat loss to development. Other threats to consider are climate change, especially in lower elevations, due to increasing temperatures and decreasing rainfall, which means less food and water sources for the bighorn sheep.

The Sespe Wilderness lies within the Western Transverse Range, and is the westernmost range for desert bighorn sheep in the western U.S. Over the last century this mysterious bighorn herd endured a bit of everything in this arid environment.

How many desert bighorn sheep reside in this wilderness is anyone’s guess. For many years the situation appeared bleak; a reintroduced herd totaling 37 bighorn from the San Gabriel Mountains 60 miles east of the Sespe was supposed to re-establish desert bighorn in this region for the first time since 1914. That was in 1985 and 1987, the then-California Department of Fish and Game (CDFG, now California Department of Fish and Wildlife, CDFW) making it a priority to bring the desert bighorn back to its historic range.

After the release of the reintroduced herd, those transplanted animals ran into several obstacles immediately following their helicopter drops. Powerful wind storms scattered the bewildered bighorn. That region of the Sespe was also overgrown with vegetation 20 feet tall in some areas, forcing the bighorn to run blindly into awaiting predators, mainly mountain lions. The heavy vegetation also didn’t allow for new growth of grasses and sages vital for their browsing. The reintroduced bighorn were fitted with radio collars, but by 1995 those radio collars fell silent.

Land surveys by biologists and volunteers were difficult due to the rugged terrain in the Sespe, but also because of the same overgrown chaparral that hindered the bighorn’s sight. Aerial surveys were limited to outside the California Condor Sanctuary, where good habitat existed. As years went by, surveys were finding fewer and fewer sheep with maybe one or two bighorn turning up per survey. Eventually, surveys came to a halt in 1992, when the last one produced only two sheep. At the same time, the San Gabriel population crashed from about 700 to only 35, which shifted conservation focus away from the Sespe bighorn sheep, causing the herd to fade somewhat into memory and take a backseat to the remaining animals in the San Gabriel range.

“Initially, we expected a high mortality rate from predation,” said Steve Torres, CDFW biologist in 2003. “There’s no surefire way to move animals successfully, and there’s lots of risks involved. To get a viable herd established is quite a masterful process.”

By 1999, however, reports by backpackers and hunters were filtering in about bighorn sightings surrounding the higher elevations of San Rafael, MacDonald and Cobblestone Peaks. Stories ranged from 18 to 28 sheep so surveys returned but bighorn numbers didn’t climb beyond that.

Day FireDesert bighorn sheep have endured a lot in the Sespe Wilderness. The combination of overhunting and disease from livestock took its toll and drove them to extinction by 1914. After the re-emergence of the reintroduced herd in the 1990s, the bighorn population in the Sespe was in a wait-and-see mode due to the overgrown chaparral. Would the population ever resume climbing or was this the limit of its growth?

Fires are essential to the survival of desert bighorn sheep. The Day Fire took care of that, one of the largest wildfires in Southern California history. It began on Labor Day of 2006 and wasn’t contained until Oct. 2. More than 4,000 firefighters fought the blaze, which was started accidentally by someone burning trash. The 254-square-mile fire cost more than $73 million to fight, and burned 162,702 acres.

Despite the devastation, the wildfire did accomplish two positive things in the Sespe. It burned overgrown chaparral that wasn’t allowing new vegetation to grow beneath its dense canopy. It also opened up valuable escape terrain for the (still-undetermined) population of desert bighorn sheep in the region.

“In principle, bighorn sheep in these coastal scrub vegetation communities benefit from fire,” said Torres. “It provides more open habitat and forage, and provides better visibility to avoid predators.”

The burn has already enabled survey crews to get a better read on the existing population. A survey in November 2012 revealed the largest number of bighorn ever seen since the initial reintroduction in the 1980s. A total of 64 sheep looking healthy and thriving was benefiting from the wide-open terrain and new growth. The survey was conducted by two CDFW biologists, volunteers and Los Padres Outfitters who supplied the mule pack train.

Christine Thompson was one of those biologists and she said this band of bighorn still needs plenty of observation. Her goal is to trap some of the sheep and attach GPS collars.

“The Sespe sheep are a big unknown,” explained Thompson. “That’s why I want to get collars on some of them. We want to know where their lambing areas are. Are they moving or staying in one place?”

Typically, peak lambing season is February through March, but it can occur from mid-December through May depending on the health of the habitat. There’s been a report of a lamb spotted in December.

“We don’t know when these bighorn are dropping lambs,” Thompson continued. “I’d like to do bighorn land surveys at MacDonald and Cobblestone Peaks. I did a fixed-wing flight over those areas and saw some trailing.”

An older ram, at least 10-years-old, with one of his ewes. He had at least 10 sheep in his herd.

Counting sheepLast summer, I heard rumblings that the small band of desert bighorn was actually hovering at the century mark. Graham Goodfield, owner/guide of Los Padres Outfitters, has spent most of his life exploring the backcountry of the Los Padres National Forest. He’s also been instrumental in leading land survey crews into the Sespe to look for bighorn. He’s also counted sheep on his own and says there are a lot of bighorn back there.

“I’m up to 128 sheep,” said Goodfield over the phone earlier this year. “I found many of them in the high country behind Willett Hot Springs.”

I needed to head out and see the recovery for myself. After spotting those 13 bighorn the night before, I lit out on my own at dawn. As I scrambled and bushwhacked my way toward San Rafael Peak at 6,666 feet, I found plenty of trailing and droppings along the way. Visibility was excellent as I scanned ridgelines searching for sheep. They, however, blend in so well in their environment that I wasn’t having much luck locating them. That was, until I heard rocks cascading into one of the few creeks still holding water.

My attention was quickly diverted to a narrow draw several hundred feet below me. Moving upward on a loose scree slope were 12 desert bighorn sheep. Several ewes and lambs stayed close to a large ram that possessed impressive curled horns. The horns on the tiniest of the lambs were just beginning to pop. I watched from above as they traversed the west face to a narrow ridgeline, feeding the entire way.

Some of the more intriguing questions surrounding these bighorn are their ages and how many generations of bighorn have lived in the Sespe Wilderness since the reintroduction.

Desert bighorn rams typically don’t live as long as the ewes. Males live 10 to 13 years, where the females live a bit longer, 12 to 20 years. “So we’re looking at third- or fourth-generation sheep in the Sespe,” said Thompson.

Another aspect surrounding the Sespe bighorn was observing a couple of herds with at least two large rams. The first herd of bighorn that Trudeau and I saw on the ridgeline at dusk revealed at least two large rams in the herd. This may be another need for collaring some of these bighorn to learn some of their behavioral traits that possibly evolved while surviving in such dense vegetation.

“Rams are usually solitary,” she said, “but the Sespe bighorn may have structured themselves where there are more than one ram per herd.”

I scrambled up and down two more canyons. At the top of the second one I looked down on top of a plateau hundreds of feet from where I stood. There was a blur of desert bighorn, running hard and heading west. I counted 20 animals before they were out of my line of sight. For a moment I thought they were being chased, but I never saw a predator in hot pursuit, just plenty of wide open space for these bighorn to roam in the Sespe Wilderness.